Focal hand dystonia, is a disorder that causes muscles of the hand, wrist and elbow to contract involuntarily. Focal hand dystonias such writer’s cramp occur when the brain sends incorrect signals to muscles in the hand, wrist, and elbow during handwriting or other fine motor tasks.
The condition most often develops in people between the ages of 30 and 50 years and progresses to the other hand in about 5% of cases. Writer’s cramp can vary in severity and include any one or a combination of the following symptoms:
Fingers gripping very tightly when holding a pen or object
Fingers straightening during the task, making it difficult to use the hands
Hand and finger weakness
Coordination and control issues in the fingers
Wrists twisting or moving at unusual angles
There are two types of writer’s cramp:
Simple writer’s cramp involves difficulty only with writing. It is most often caused by holding the pen improperly, poor posture when writing and overuse.
Dystonic writer’s cramp — also known as mogigraphia — can occur in any type of fine motor activity. Symptoms may happen not only during writing, but also when doing other tasks with your hands — like shaving or buttoning a shirt. This condition is less common than simple writer’s cramp.
Focal hand dystonias may be related to abnormalities of connections established in the motor cortex, basal ganglia and cerebellum that impact the cortical representation and inhibition of motor programs. The condition may also be related to impaired sensorimotor integration and abnormal sensory tactile perception.
You can reduce your risk for developing simple writer’s cramp by:
Focusing on good writing posture and technique.
Using pens and tools with larger grips.
Avoiding fatigue and overuse.
Treatment of focal hand dystonias must be individualized. Interventions may include:
Oral anticholinergic drugs which be helpful by affecting the transmission of signals from the brain to the muscles.
Botulinum toxin (Botox) injections can be used to block the nerve impulses to the cramping muscles and temporarily weaken them while new movement patterns are learned.
Physical and occupational therapy can help with improving writing posture and hand positioning as well as recommend writing aides or specialized splints. Therapy may also provide sensory re-education and sensory motor returning to retrain brain connections and movement patterns that cause writer’s cramp.